from Glen Yakimoff , Newcastle Australian Plants Society
Genetic variabllity helps plant species try to develop better strains that
can keep ahead of climate and pest changes, with the weaker strains dying
off and the more tolerant strains surviving. Pests will improve their own
genetic strains, and if plants aren't allowed to do the same pests could
possibly become worse as the plants cannot similarly evolve to keep pace
with the pests!!! Pests can certainly evolve to become resistant to
pesticides, and that is why biological controls can be more effective in the
long term, as long as proper research is done before any biological methods,
eg insects, are released into the environment. Here in Australia there are a
number of companies that sell biological controls such as insects!!!
Also of interest is the following extract from the September 1998 article of
the journal "Australian plants":-
"Mt read (1,157 metres), in the central west of Tasmania is somewhat
renowned for it botanical treasures. In recent years a one hectare "stand"
of Huon Pines was found on the southern slopes of Mt read, at about 950m and
a little upstream from a small glacial tarn, lake Johnston. The locality is
quite unusual for huon Pine, its "normal" habitat being cool lowland
rainforest, bordering rivers and estuaries in the west and south-west of
Tasmania.
Subsequently studies of this "forest" have revealed that is is not a stand
of the species but a single tree, a male tree at that! The evidence
indicates that the one lone male tree - all material examined is genetically
identical - has been reproducing itself vegetatively for the past 10-11
THOUSAND years.
Huon pine grows readliy from cuttings or layers and it is likely that heavy
snowfalls have bent the supple branches to the ground during winter where,
in spring, they have taken root and thus continued the species. It must be
pointed out that the living tree of today is not 10-11,000 years old and
still alive." etc , etc ,etc "sediment cores from nearby lake Johnston have
revealed pollen from this "tree" ..... was present ..... 22,000 years
ago"!!!